Mercedes G-Class (2018)

Estimated running costs and MOT pass rates from 807 MOT tests in 2024.

Annual Cost

£2,131

£178/month

MOT Pass Rate

94%

Excellent

Road Tax

£200

Standard rate/year

Est. Insurance

Grp 30-42

2987cc Diesel

Great Choice

94% pass rate, £2,131/year to run. 12 points above average.

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Diesel2987cc8 years old807 tests39k miles avg

Annual Running Costs

Fuel (Diesel, 2987cc)

~40 mpg

£1,676

Road Tax

Standard rate (from April 2017)

£200

MOT Test

£55

Predicted Repairs

Low estimate due to excellent reliability

£200

Total per year£2,131

Per month£178/mo

Per week£41/wk

Estimates based on 7,400 miles/year (UK average), diesel at 199.33p a litre (GOV.UK weekly average, week of 19 October 2026), GOV.UK road tax rates and repair likelihood from MOT data. Insurance not included. Cars registered from April 2017 pay the £200 standard rate, plus £440 a year for five years (from the second year) if they cost over £40,000 new (over £50,000 for electric cars).

Reliability Verdict

94% MOT pass rate(Excellent)

0%All-model avg: 82%100%

Excellent reliability. Very few MOT failures. That's 12 points above the average of 82% across all models in our data. It also outperforms the Mercedes brand average of 87%.

94% of MOT tests on Mercedes G-Classs from 2018 ended in a pass in 2024, when they were about 6 years old. That's based on 807 tests across the UK, retests included. The average mileage recorded at those tests was 39,199 miles.

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How Does It Compare?

Rank among 2018 models120th of 607(top 20%)

Rank among Mercedes models299th of 1,376(top 22%)

vs average of all models+12%(82% avg)

vs 2018 models average+5%(89% avg)

vs Mercedes average+7%(87% avg)

Mileage Analysis

39,199

Average miles

44,400

Expected for age

The average 2018 Mercedes G-Class had 39,199 miles on the clock at its 2024 MOT, which is in line with the expected 44,400 miles for a 6-year-old car, suggesting normal everyday use.

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Best Year to Buy?

Of the years with at least 100 tests, the 2019 model has the highest MOT pass rate at 96%, while the 2017 model has the lowest at 86%. The 2018 scores 94%. Newer cars usually pass more often simply because they are younger, so compare years of a similar age.

Mercedes G-Class by Year

Year	Pass Rate	Tests	Avg Mileage
2021	78%	65	30,190 mi
2020	98%	66	32,570 mi
2019	96%	319	41,698 mi
2018	94%	807	39,199 mi
2017	86%	691	43,730 mi
2016	94%	604	58,012 mi
2015	88%	591	48,991 mi
2014	92%	362	54,969 mi
2013	94%	449	69,675 mi
2012	90%	221	76,209 mi
2011	96%	92	70,666 mi
2010	73%	33	78,145 mi
2007	100%	35	103,461 mi
2001	60%	42	93,234 mi
1999	82%	44	113,541 mi

Similar Cars to Consider

Mercedes E

2019 · 2925cc Diesel

£2,131/year

90%

-4%

Mercedes GLC

2018 · 2987cc Diesel

£2,131/year

91%

-3%

Audi A5

2017 · 2967cc Diesel

£2,281/year

89%

-5%

Ford Ranger

2019 · 3198cc Diesel

£2,281/year

87%

-7%

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About the 2018 Mercedes G-Class

The 2018 Mercedes G-Class is a premium performance car. Our records list a 2987cc diesel engine, though engines vary between versions. 807 MOT tests were recorded on this model in 2024, making it a less common model in the UK market. It ranks in the top 20% of all 2018 models for MOT pass rate.

With an average of 39,199 miles recorded at its 2024 MOT tests, Mercedes G-Class owners drive about as much as the UK average.

2018 Mercedes G-Class Fuel Costs

The 2987cc diesel engine is on the larger side, so fuel won't be this car's strong point. Expect around 40 mpg in mixed driving, which works out to roughly £1,676 per year with diesel at 199.33p per litre (GOV.UK weekly average, week of 19 October 2026; based on 7,400 miles per year). Diesel cars of this age should have their DPF (diesel particulate filter) checked, as replacements can be costly.

What does it cost to own a 2018 Mercedes G-Class?

Total estimated annual running cost is £2,131 (£178/month), broken down as £1,676 fuel, £200 road tax, £55 MOT, and £200 predicted repairs. The low repair estimate reflects the excellent 94% pass rate. These cars rarely fail their MOT, so unexpected bills are less likely.

Mercedes G-Class Reliability Trend

The Mercedes G-Class has maintained consistent MOT pass rates across model years, varying by only 2 percentage points.

Buying a Used 2018 Mercedes G-Class

At 8 years old, this is a solid used buy if you find one with good service history. Depreciation has levelled off, so you won't lose much more value. Focus on condition over mileage. If you're flexible on year, the 2019 model has the highest pass rate at 96%.

Common Issues to Watch For

These are typical issues for cars of this age, fuel type and engine size, not faults recorded on this model's MOT tests. Use them as a checklist when you view one.

DPF (Diesel Particulate Filter)

Watch out

Short journeys clog the DPF. Replacement costs £1,000-£2,500. Check the DPF warning light and ask about driving patterns.

Turbo Wear

Watch out

Diesel turbos work harder and wear faster. Listen for whining noises and check for oil leaks around the turbo housing.

AdBlue System

Medium risk

Post-2015 diesels use AdBlue for emissions. Sensor failures and tank heater issues are common. Budget £200-£500 for repairs.

EGR Valve

Watch out

Exhaust Gas Recirculation valves clog with carbon deposits, causing rough running and poor economy. Cleaning costs £150-£300, replacement £300-£600.

Dual Mass Flywheel

Watch out

Larger diesel engines put extra strain on the dual mass flywheel. Listen for rattling at idle. Replacement with clutch is £800-£1,500.

Suspension Wear

Medium risk

Shock absorbers, springs, and anti-roll bar links typically need attention around this age. Listen for clunks over bumps and check for uneven tyre wear.

Service History

Low risk

Always request a full service history. Regular servicing is the single best indicator of how well a car has been maintained, regardless of mileage.

Running Costs Compared

How the 2018 Mercedes G-Class stacks up against similar cars for estimated annual running costs, insurance group, and tax.

Car	Pass Rate	Fuel/yr	Tax/yr	Est. Ins. Group	Total/yr
Mercedes G-Class(2018)	94%	£1,676	£200	Grp 30-42	£2,131
Mercedes E(2019)	90%	£1,676	£200	Grp 30-42	£2,131same
Mercedes GLC(2018)	91%	£1,676	£200	Grp 30-42	£2,131same
Audi A5(2017)	89%	£1,676	£200	Grp 30-42	£2,281+£150
Ford Ranger(2019)	87%	£1,676	£200	Grp 35-50	£2,281+£150

Estimates based on 7,400 miles/year, GOV.UK average pump prices for the week of 19 October 2026, GOV.UK road tax rates and MOT data. Insurance groups are our rough estimate from engine size, not official groups. Actual costs vary by driver, location, and usage.

Questions about the 2018 Mercedes G-Class

Is the 2018 Mercedes G-Class reliable?

Excellent reliability. Very few MOT failures. 94% of MOT tests on 2018 Mercedes G-Classs ended in a pass, from 807 tests (DVSA MOT data for tests in 2024, retests included). That's 12 points above the average of 82% across all models in the same data.

How much does a 2018 Mercedes G-Class cost to run?

Our estimate is £2,131 a year (£178 a month): £1,676 fuel, £200 road tax, £55 MOT and £200 predicted repairs, based on 7,400 miles a year. Insurance is not included.

What is the MOT pass rate for a 2018 Mercedes G-Class?

94% of 807 MOT tests on the 2018 Mercedes G-Class ended in a pass (DVSA MOT data for tests in 2024, retests included). That ranks it 120th of 607 models first registered in 2018 (top 20%).

Which year Mercedes G-Class has the best MOT pass rate?

Of the years with at least 100 tests, the 2019 Mercedes G-Class has the highest MOT pass rate at 96% and the 2017 the lowest at 86%. Newer cars usually pass more often simply because they are younger and have done fewer miles.

What is the average mileage for a 2018 Mercedes G-Class?

The average mileage recorded at MOT tests on the 2018 Mercedes G-Class is 39,199 miles, which is in line with the expected 44,400 miles for a 6-year-old car, suggesting normal everyday use.